Flighting for dehydrator drum

ABSTRACT

A dehydrator includes a drum having an inlet and an outlet mounted for rotation about its longitudinal axis. Internal flighting for facilitating uniform drying of material passed through the drum includes a plurality of circumferentially spaced vanes which are rigid with the inner surface of the drum. At least a portion of the vanes are provided with laterally extending cleats which break up clumps of material falling off the vanes. Centrally disposed in the drum is another arrangement of flighting which acts as a retainer for catching material which gravitates from the aforementioned vanes. The central flighting comprises a shaft with a plurality of longitudinally extending axially projecting plates having one or more interference structures traversing the plane of a plate at oblique angles. When a pair of structures are utilized they are disposed in either parallel or perpendicular relationship to each other.

United States Patent 91 Thompson a 1 Feb. 27, 1973 [76] lnventor:Stanley P. Thompson, 2718 Osborn Rd, Topeka, Kans. 66614 [22] Filed:April 19, 1971 [21] Appl. No.: 135,078

Related US. Application Data [63] Continuation-impart of Ser. No.773,188, Nov. 4,

1968, Pat. NO. 3,593,430.

- FOREIGN PATENTS OR APPLICATIONS 362,969 Germany ......34/135 PrimaryExaminer-Milton Kaufman Assistant Examiner-Theophil W. StrculcAttorney-Bradley and Wharton [57] ABSTRACT A dehydrator includes a drumhaving an inlet and an outlet mounted for rotation about itslongitudinal axis. Internal flighting for facilitating uniform drying ofmaterial passed through the drum includes a plurality ofcircumferentially spaced vanes which are rigid with the inner surface ofthe drum. At least a portion of the vanes are provided with laterallyextending cleats which break up clumps of material falling off thevanes. Centrally disposed in the drum is another arrangement offlighting which acts as a retainer for catching material whichgravitates: from the aforementioned vanes. The central flightingcomprises a shaft with a plurality of longitudinally extending axiallyprojecting plates having one or more interference structures traversingthe plane of a plate at oblique angles. When a pair of structures areutilized they are disposed in either parallel or perpendicularrelationship to each other.

9 Claims, 11 Drawing Figures PATENTEI] FEB 2 7 I975 sum 2 0P3 INVENTORL57an ley P Thompson M 40/42:

4 f farneys FLIGH'IING FOR DEHYDRATOR DRUM This application is acontinuation in part of my previously filed application Ser. No. 773,188 entitled Crop Dehydrator and filed Nov. 4, 1968 now U.S. Pat. No.3,593,430. I

An important consideration in the drying of any material isproperdistribution of the material to be dried within the drying acne.Distribution is a particular problem in the drying of crops such asalfalfa because of the tendency for the crop to bunch together. Thisresults in inadequate drying of some of the alfalfa and overdrying andeven charring of some of the alfalfa.

It is the normal process to dry crops such as alfalfa within elongatedrotatable drying drums which continuously rotate to help distribute thecrop being dried. It has also been the practice to incorporate flightingaround the periphery of the drying drum to further facilitate evendistribution. In spite of improvements inthe field of dehydratingapparatus, it is recognized that even distribution of a material to bedried, and particularly crops such as alfalfa which tend to bunch, is aproblem which has not been completely solved.

It is therefore an object of the present invention to provide adehydrator having flights of vanes strategically positioned and shapedto distribute the material as uniformly as possible across the entirecross section of the drum to cause maximum transfer of heat from the hotgases of combustion to the material as the latter travels through therotating drum.

In carrying out the preceding object it is also another object of theinvention to provide vanes configured to permit automatic separation ofrelatively light or leafy material from heavier or stemmy material sothat the lighter particles may be carried out of the drum by the airstream in advance of the heavier particles, which require further timein the drum to achieve a uniformly dried product.

Still another object of the invention is a flighting arrangement for arotating drying drum which incorporates cleat structure on the vanes ofthe flighting to facilitate breakup of any bunches of the material beingdehydrated.

An important aim of this invention is also to provide a drying drumhaving flighting arranged both around the periphery of the drum andcentrally within the drum to assure breakup of I the material beingdehydrated as it falls from the outer peripheral flighting as thedrum'rotates.

It is also one of the aims of the present invention to permit uniformpneumatic conveying of a material to be dried through a drying drum byincorporating flighting within the drum to assure that all of thematerial being dried falls a uniform distance as it gravitates from oneside of the drum to the other as the drum rotates.

.As a corollary to the aim of the invention set forth above, one of theobjects of the invention is also to maximize the minimum distance whichany material falls in gravitating from one side of the drum to theother, yet assuring that this distance is uniform for all of thematerial.

In the drawings:

' FIG. 1 is a fragmentary, side elevational view on a reduced scale andpartially schematic of a dehydrator system incorporating the principlesof this invention,

to reveal details of construction;

FIG. 2 is a vertical, cross-sectional view through the dehydrator drumtransversely thereof;

FIG. 3 is a fragmentary, vertical cross-sectional view through the drumlongitudinally thereof, the flighting appearing in elevation;

FIG. 4 is a schematic vertical cross-sectional view taken longitudinallyof the drum with the internal flighting removed to illustrate analternative form of hanger arrangement for supporting the central shaftupon which a portion of the flighting is mounted;

FIG. 5 is an enlarged, vertical cross-sectional view taken transverselyof the drying drum with the central flighting removed and illustratingin further detail the alternative hanger arrangement for securing thecentral shaft axially of the drum;

FIG. 6 is an enlarged, fragmentary view looking at the end of thecentral shaft and further illustrating the hanger arrangement;

FIG. 7 is an enlarged, fragmentary side elevational taken transverselyof the drying drum and illustrating an alternative form for the centralflighting which is disposed about the axially aligned shaft;

FIG. 9 is an enlarged, fragmentary, side elevational view of the slopingT-bar which forms a part of the central flighting, with an alternativeposition for the trans verse member illustrated in broken lines;

FIG. 10 is an enlarged, fragmentary, side elevational view similar toFIG. 9 and illustrating an optional intermediate cleat shown disposed onthe T-bar; and

FIG. 11 is an enlarged,'fragmentary, side elevational view similar toFIGS. 9 and 10 and illustrating an optional second transverse memberdisposed on the T-bar with an alternative position for this optionalmember being shown in broken lines.

Referring initially to FIG. 1 of the drawings, the dehydrator of thisinvention includes an elongated, cylindrical drum 10 having a sidewall12 and an outlet end wall 14. A furnace 16 communicates with the inletend of drum 10 and a fan broadly designated 18 is interposed in amaterial discharge conduit 20 which communicates with the outlet end ofdrum 10 through a discharge opening 22 best seen in FIG. 7. A materialinlet conveyor 24 is provided adjacent furnace 16 at the inlet end ofdrum 10 for the purpose of introducing the material to be dehydratedinto the drum. The latter is mounted for rotation about its longitudinalaxis on roller means 26 and is powered by drive means (not shown) toeffect rotation of the drum in the direction of the'arrow in FIG. 2.

Furnace 16 includes a blower 28 for providing air to be mixed with thefuel which is introduced into furnace 16 through a fuel line 30. The hotgases of combustion are directed into the interior of drum [0 for dryingthe material as the latter progresses'through the drum. To

this end, blower or fan 18 serves to draw the gases parts being brokenaway and revealed in cross section through the drum so that the driedmaterial is drawn toward outlet opening 22 and into conduit 20. It willbe understood that conduit 20 may communicate with a cyclone separatoror the like (not shown) so that the dehydrated material may be separatedfrom the airstrearn for further processing as: may be desirable orrequired.

In the drying of hay or other materials it is particularly importantthat as much surface area of the material particles as possible beexposed to the drying influence of the hot gases passing through thedrum. To this end, the interior of drum is provided throughout itslength with a flighting adapted to engage the material upon rotation ofthe drum and to distribute the material as uniformly as possible acrossthe entire hollow cross section of the drum. Manifestly, upon lifting ofthe material to a given position as the drum rotates, the material isdropped for gravitation toward the bottom of the drum. The material isthereupon again lifted by the flighting for subsequent distribution topermit gravitation of the particles of material through the hot streamof gases and toward the bottom of the drum whereupon the processcontinues successively until the material is sufficiently dehydrated tobe carried to the discharge end of the drum by the hot gases.

The flighting to accomplish the foregoing operation on the material inthe drum includes a plurality of vanes secured in annular rows to theinner surface of the cylindrical drum wall 12. Each row of vanesincludes a series of differently shaped vanes. Thus, a vane 32 comprisesa substantially flat generally planar panel 34 having one end thereofsecured as by welding or the like to the inner surface of wall 12. Thepanel 34 extends radially inwardly of the drum and terminates in a lip36 at the end of panel 34 remote from wall 12. Thus, the ou- -termostend of each vane travels in a first circular path during rotation of thedrum.

The next successive vane 38 in the row proceeding in a counterclockwisedirection is spaced circumferentially from vane 32 and comprises a panel40 having one marginal edge thereof secured as by welding or the like tothe inner surface of sidewall 12 similar to the attachment of panel 34to the drum. It should be noted, however, that the panel 40 is providedwith aline of bend 42 in spaced relationship from wall 12 and from theinnermost end of the panel. Thus, the panel comprises a portionextending radially inwardly of the drum and a second portion deviates atan angle from the direction of the first portion as illustrated. clearlyin FIG. 2. The outermost end of panel 40 is provided with a lip 44similar to lip 36 of panel 34.

The next successive vane 46 of the series of vanes is similar to vane 38in that it is provided with a line of bend 48 intermediate its ends.However, the angle of bend of the portions of the vane 46 is such thatthe vane is straighter than vane 38. Again, vane 46 is provided with alip 50 at its innermost end. Although the specific arrangement of thedifferent vanes in the series depicted has been found desirable, otherarrangements for the vanes will also produce advantageous results.

Referring to FIGS. 2 and 3, it may be seen that each row 52 of vanes maybe identical to the adjacent rows but it has been found to be desirablethat each successive row longitudinally of the drum be rotated withrespect to the preceding row. Thus, a vane 32 is not directly adjacentan identical vane 32 of the adjacent row. Rather, it is adjacent a vane38 or a vane 46. Similarly, the vanes 42 and 46 are disposed besidedissimilar vanes of the adjacent row.

Certain of the vanes are provided intermediate their lengths with cleats54 which may be formed .of key stock material welded to the leadingsurface of the vane. The cleats 54 serve to retard the slippage of thematerial along the surface of the vane for a purpose to be more fullyexplained hereinafter.

A longitudinally extending shaft 56 is disposed axially of drum l0 andis secured to the latter by a plurality of hangers 58. Each hanger 58includes an arcuate portion 60 having one end thereof secured to theouter surface of shaft 56 by welding or the like and an integralstraight portion 62 having its outermost end welded to the inner surfaceof drum 10. It will be understood that as many hangers 58 are providedas are necessary for securing the shaft in its proper position. Further,the provision of the arcuate portion 60 disposed in a wrapped-aroundmanner adjacent the outer surface of shaft 56 insures that the latter ismaintained in its proper axial position even when the hangers 58 andshaft 56 are exposed to the extreme temperatures caused in drum 10 bythe hot dehydrating gases provided by furnace 16. It should be notedthat the straight portions 62 of hangers 58 extend tangentially of shaft56 so that heating of the hangers 58 merely causes a rotation of shaft56 without moving the latter from its axial position.

Shaft 56 mounts a plurality of vanes 64 extending radially outwardlyfrom the shaft. The vanes 64 are connected with brace members 66 asillustrated best in FIG. 2. Further. each vane 64 is provided with acleat 68 on its leading and its trailing surface to reduce the slippageof material on the vane. Shaft 56 rotates with the drum 10 therebyrotating the vanes 64.

Referring now to FIGS. 4-7 where the alternative hanger arrangement forthe shaft 56 is illustrated, it is seen that the shaft is again held bya plurality of hangers 158. Each hanger 158 includes an arcuate portion160 which at least partially surrounds the shaft 56, and a pair oflongitudinally extending straight portions 162 and 162' which areintegral with and extend from the opposite ends of the arcuate portion160. The outermost ends of the straight portions 162 and 162' arerigidly secured to the inner surface of the sidewall 12 by welding orother appropriate means. It may also be desirable'to spotweld thearcuate portion 160 to the shaft 56. It is desirable to provide three ofthe hangers 158 at each supporting location of the shaft 56 with thehangers being disposed in a complemental arrangement as best illustratedin FIG. 6. In this manner, the arcuate portions 160 essentiallycompletely surround the shaft 56, and as is clear from viewing FIG. 7,the shaft is precluded from moving in any direction away from the centerof the drum 10.

It will also be noted from viewing FIG. 5, that each of the vanes 32, 38and 46 is provided with a cleat 54 as previously described for theembodiment of FIGS. l-3. In this alternative form, however, instead ofutilizing the cleats 54 only on selected vanes, each of the vanes isprovided with the intermediate cleat 54. It has also been founddesirable in certain instances to provide a gusset plate 70 between eachof the vanes 32, 38 and 46 and the drum wall 12 to strengthen the vanesand reduce the possibility of breakage.

In FIGS. 8 and 9 an alternative central flighting arrangement has beenillustrated and designated generally by the numeral 72. The centralflighting 72 comprises a plurality of longitudinally extending, radiallyprojecting vanes or plates 74 which are secured to theshaft 56 at oneend by fluting, welding or the like and are further supported by aplurality of brace bars 76 which extend between successive plates 74 andare welded to the latter. The other end of each plate 74 extendsoutwardly into the drum for travel in a second circular path spacedcircumferentially inwardly from the path of travel of the ends of thevanes secured to the inner surface of the drum. It is to be understoodthat each of the plates 74 which is visible in FIG. 8 is the first in alongitudinally extending row of the plates. Thus there are a pluralityof the plates 74 disposed in end-to-end, closely spaced relationship inrows which extend longitudinally of the shaft 56. Each of the plates 74is provided with a plurality of interference structures such as crossmembers 78 disposed at the outermost ends of the plates 74 and securedthereto by welding or the like, with gusset plates 80 providingstructural support. It is to be understood that while only one of thecross members 78 is illustrated at the end of each of the plates 74 inFIG. 8, a number, of the members 78 would normally be disposed inclosely spaced relationship at intervals along the entire length of eachof the plates. Similarly, a number of cross braces 76 are normallyprovided at spaced intervals along the length of the shaft 56. The crossmembers 78 .are generally planar, longitudinally extending structures ofany desired cross section. Thus, each of the members 78 cooperates withthe plate 74 to form a T-bar which is highly instrumental infacilitating aneven distribution of a crop such as alfalfa whilepreventing bunching of the alfalfa as it is distributed in the drum 10.Each of the members 78 is provided with laterally extending cleatprojections 82 and 84 at its respective ends. As illustrated in FIG. 10,it is sometimes desirable to provide a third cleat projection 86 whichextends laterally of the member 78 intermediate the previously twomentioned cleat projections 82 and 84.

As clearly shown in FIG. 9, the member 78 is disposed to transverse theplane of the plate 74 to which it is attached at an oblique angle. Whilereasonable variations in the angle can be tolerated, it has been foundthat an angle of approximately 45 is particularly advantageous foroptimum results in facilitating even distribution of a material to bedehydrated. As indicated by the phantom illustration in FIG. 9, this 45angle between the member 78 and the plate 74 can be formed by slopingthe member 78 in either one of two directions. While various positionsintermediate the two positions shown in FIG. 9 for the member 78 areacceptable, in general an angle of from 25 to 45 between the member anda corresponding plate 74 is desirable.

Referring now to FIG. 11 wherein an alternative arrangement for thecentral flighting 72 is illustrated, it is seen that in addition to theinterference structure formed by the member 78, a second interferencestructure which is formedby a pair ofaligned cross members 88 and 90 isdisposed in spaced relationship to the member 78 inwardly therefromalong the plate 74. Although the members 88 and 90 are shown in alignedrelationship in FIG. 11, it is to be understood that while this is thepreferred arrangement, the members can be disposed at other locationsalong the plate 74. Each of the members 88 and 90 is of generally thesame configuration as the cross members 78, although slightly shorter inlength, and is rigidly secured to the plate 74 in a manner similar tothe member 78. Each of the members 88 and 90 is provided with alaterally extending cleat projection 92 at its end which projectionsgenerally complement the projections 82 and 84 on the members 78. Thecommon plane of the members 88 and 90 transverses the plane of the plate74 at an oblique angle as previously described for the member 78. Theangle between each of the members 88 and 90 and the corresponding plate74 is againpreferably 45, and in no case should it be less than 45,although this angle may be formed with the members 88 and 90 disposedeither parallel or perpendicular to the member 78 as shown by thephantom illustration in FIG. 11.

In operation, fuel is burned in the furnace l6 and the hot combustiongases are directed into the drum by blower 28. The material to be driedis conveyed to the interior of the drum by conveyor 24, and the drum 10is rotated on its longitudinal axis to distribute the materialthroughout the interior of the drum. The fan or blower 18 is alsooperated to insure a sufficient flow of combustion gases and airlongitudinally of the drum to pneumatically convey the material being,dried.

The rotating drum constantly moves the vanes in a counterclockwisedirection as viewed in FIG. 2 so that the material in the drum is pickedup by the vanes as they rotate along their lowermost positions withinthe drum. The material is retained on the vanes as the same is liftedthereby until the vane reaches a position along its path of travel wherethe vane drops the material for gravitation across the drum toward thebottom of the drum. The different shapes of the vanes insure that thematerial release point for the various vanes is reached at differentpositions of rotation of the drum. Thus, a substantially uniform curtainof material in relatively small clumps is alternatively picked up andthen released by the successive vanes for gravitation across the drum.It has been found that clumps of material being dried have a tendency toslide toward the edges 7 of the vanes 32, 38 and 46, and in someinstances a clump of material will actually pivot over the upwardlyprojecting lips 36, 44 and 50 respectively to continue as a clump as itgravitates across the drum. For this reason, the cleats 54 are extremelyimportant in assuring a breakup of any bunches of material before thelip of the respective vane is reached. The result is that the materialtends to dribble downwardly from the terminal edge of the vane andclumping is largely eliminated.

Since the conveying media comprised of combustion gases and air from theatmosphere is regulated so as to be incapable of supporting the materialbeing dried against gravitation until a portion of the water has beenremoved from it, a portion of the material gravitates from the vanes 32,38 and 46 toward the center of the drying drum.

The central vanes 64 or 74, however, prevent the material fromgravitating to the bottom of the drum by the corresponding vanes 32, 38and 46. The shortened paths of gravitation of the material insures thatthe gas flow through the drum does not have sufficient time to act onthe material while falling to move the material through the drum at toofast a rate for proper drying.

The utilization of the central vanes 74 with members 78 disposedtransversely thereof has been found to be particularly useful infacilitating even distribution of material throughout the drum 10. Itwill be appreciated that the cross members 78 at the ends of the vanes74 provide an extension of the vanes in the direction of the peripheralvanes 32, 38 and 46, thereby reducing the possibility of any of thematerial falling past the vanes 74 without being caught. At the sametime, the members 78 interfere substantially with the dumping ofmaterial from the vanes 74 as the latter rotate through their circuitouspaths of travel, thus further breaking up any clumps of material andachieving the same dribbling action in the lower half of the drum 10 asis achieved in the upper half by the vanes 32, 38 and 46.

The incorporation of the optional intermediate cleats 86 and theoptional interference structure comprised of cross members 88 and 90depends largely on the nature of the material being dried and the needfor further breakup and distribution of the material.

The cleats 54, 68, 82-86, and 90-92 on the respective vanes further tendto dribble the material from the vanes rather than releasing the same ina clump when the vane reaches a position for discharging material. Thisalso serves to enhance the distribution of the material uniformly acrossthe drum for maximum exposure of the material to the hot gases ofcombustion for dehydrating the material.

Not to be overlooked is the effect of the rows of vanes which aredisposed in series and in offset relationship longitudinally of thedrum. This arrangement for the vanes which are secured to the innersurface of the cylindrical sidewall 12 retards against the material frombunching as the material moves longitudinally through the drum.

From the foregoing description, it is apparent that a method ofdehydrating a crop is presented which includes providing a drying zoneat a sufficiently elevated temperature to effect removal of water fromthe crop. The drying zone is confined to a longitudinally extendingcylindrical area and drying gases are directed longitudinally throughthe zone. Next, the crop to be dried is pneumatically conveyed throughthe drying zone with the conveying media being regulated so as to beincapable of supporting the crop against gravitation until a portion ofthe water has been removed therefrom This results in a portion of thecrop gravitating to the outer periphery of the drying zone. This portionof the material is then moved toward the center of the zone by elevatingthe same and then allowing it to gravitate through the conveying mediatoward the center of the zone. Before reaching the center, however, theportion is caught and held for a period of time during which it isrotated within the drying zone to further effect removal of watertherefrom. The previously caught material is then dumped at a pointcircumferentially spaced from the point where it was caught to redirectit through the conveying media to the outer periphery of the zone.

The steps of moving a portion of the material through the conveyingmedia toward the center of the zone, catching the portion as it travelstoward the center, holding the previously caught material and thenredirecting it toward the outer periphery of the zone. are continuouslyrepeated until a sufficient amount of water has been removed from thematerial to allow the conveying media to support the same and remove thematerial from the drying zone.

By the present method even distribution of the material being dried ispermitted to a degree heretofore not possible, and the detrimentalbunching of materials such as alfalfa is largely eliminated. It isinherent in the method that the heavier stemmy materials commonly foundin crops such as alfalfa and which require significantly more dryingtime than the relatively light leafy materials also present, are heldwithin the drier for the additional time required, while the lightermaterial is removed through the conveying airstream. This greatlyreduces the danger of the lighter leafy materials being charred fromoverdrying and at the same time assures that the heavier materials willbe adequately dried.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. In a dehydrator including an elongated drum having a material inletand an outlet, means mounting the drum for rotation about itslongitudinal axis, and furnace means for providing hot gases ofcombustion to the drum, means in the drum for distributing the materialacross the drum comprising:

a plurality of generally planar circumferentially spaced vanes extendingaround the inner surface of the drum,

one end of each vane being secured to said inner surface, the other endprojecting inwardly therefrom, said other end traveling in a firstcircular path during rotation of the drum; lip carried by each vanerespectively at the end thereof remote from the inner surface of thedrum, each of said lips projecting at an angle from the plane of thecorresponding vane to retard slippage of material from the vane untilthe latter reaches a material discharging position during rotation ofthe drum; first cleat means carried by at least a portion of said vanes,said cleat means being secured to the surface of a respective vane ingenerally perpendicular relationship to the latter and disposedintermediate the drum and the lip; plurality of axially and radiallydisposed longitudinally extending generally planar retainer platespositioned in spaced relationship to each other and to said vanes forcatching material gravitating from said vanes, each of said plateshaving one end extending outwardly into said drums, said one end of saidplate traveling in a second circular path spaced circumferentiallyinwardly from said first path; generally planar longitudinally extendinginterference structure secured to each of said plates and extendingtransversely on either side of the latter to provide a drying area forsaid material prior to the material reaching the area between adjacentplates; and second cleat means disposed on said structure and extendinglongitudinally of the latter in generally perpendicular relationship tothe plane of the ship to the first-mentioned structure and traversingthe plane of said one plate at an oblique angle.

6. The invention of claim 5, wherein said second structure is disposedin parallel relationship to the firstmentioned structure.

7. The invention of claim 5, wherein said second structure is disposedin perpendicular relationship to the first-mentioned structure.

8. The invention of claim 1, said retainer means comprising a shaftextending axially of the drum and including a plurality of elongatedsupports coupling said shaft with the drum, each support having one endsecured to the shaft, an arcuate stretch adjacent said one end extendingat least partially around the shaft, and a portion integral with saidstretch spanning the distance across said drum, said portion beingrigidly secured to said drum.

9. The invention of claim 8, wherein each of said supports includes asecond portion integral with said stretch at the end of the latteropposite the first-mentioned portion and spanning the: distance acrosssaid drum, said second portion being rigidly secured to said drum.

1. In a dehydrator including an elongated drum having a material inletand an outlet, means mounting the drum for rotation about itslongitudinal axis, and furnace means for providing hot gases ofcombustion to the drum, means in the drum for distributing the materialacross the drum comprising: a plurality of generally planarcircumferentially spaced vanes extending around the inner surface of thedrum, one end of each vane being secured to said inner surface, theother end projecting inwardly therefrom, said other end traveling in afirst circular path during rotation of the drum; a lip carried by eachvane respectively at the end thereof remote from the inner surface ofthe drum, each of said lips projecting at an angle from the plane of thecorresponding vane to retard slippage of material from the vane untilthe latter reaches a material discharging position during rotation ofthe drum; first cleat means carried by at least a portion of said vanes,said cleat means being secured to the surface of a respective vane ingenerally perpendicular relationship to the latter and disposedintermediate the drum and the lip; a plurality of axially and radiallydisposed longitudinally extending generally planar retainer platespositioned in spaced relationship to each other and to said vanes forCatching material gravitating from said vanes, each of said plateshaving one end extending outwardly into said drums, said one end of saidplate traveling in a second circular path spaced circumferentiallyinwardly from said first path; generally planar longitudinally extendinginterference structure secured to each of said plates and extendingtransversely on either side of the latter to provide a drying area forsaid material prior to the material reaching the area between adjacentplates; and second cleat means disposed on said structure and extendinglongitudinally of the latter in generally perpendicular relationship tothe plane of the structure to retard slippage of material from thestructure during rotation of the drum.
 2. The invention of claim 1,wherein said structure forms an angle from about 25* to 45* with saidone plate.
 3. The invention of claim 2, wherein said second cleat meanscomprises first and second cleat projections at opposite ends of saidstructure.
 4. The invention of claim 3, and a third cleat projectionintermediate said first and second projections.
 5. The invention ofclaim 1, and second interference structure secured to said one plate inspaced relationship to the first-mentioned structure and traversing theplane of said one plate at an oblique angle.
 6. The invention of claim5, wherein said second structure is disposed in parallel relationship tothe first-mentioned structure.
 7. The invention of claim 5, wherein saidsecond structure is disposed in perpendicular relationship to thefirst-mentioned structure.
 8. The invention of claim 1, said retainermeans comprising a shaft extending axially of the drum and including aplurality of elongated supports coupling said shaft with the drum, eachsupport having one end secured to the shaft, an arcuate stretch adjacentsaid one end extending at least partially around the shaft, and aportion integral with said stretch spanning the distance across saiddrum, said portion being rigidly secured to said drum.
 9. The inventionof claim 8, wherein each of said supports includes a second portionintegral with said stretch at the end of the latter opposite thefirst-mentioned portion and spanning the distance across said drum, saidsecond portion being rigidly secured to said drum.